Method of barking logs



fi 1951 R. D. PAULEY ET AL METHOD OF BARKING LOGS 2 SHEETS-SHEET 1 FiledAug. 20, 1946 7 7- TE A/5 W5 Dec. 4, 195]! R. D. PAULEY ET AL METHOD OFBARKING LOGS 2 SHEETSSHEET 2 Filed Aug. 20, 1946 //\/Z/=/\/ TURE ROBERTD. PAULEY LOUIS A. M CAHNA E7 4 7' TU /v5 W5 Patented Dec. 4, 1951METHOD OF BARKING LOGS Robert D. Pauley and Louis A. McCanna, Longview,Wasln, assignors to Weyerhaeuser Timber Company, Longview, Wasln, acorporation of Washington Application August 20, 1946, Serial No.691,762

9 Claims. 1

This invention relates to a novel and improved method for removing thebark from logs.

Various methods have heretofore been employed for removing bark fromlogs, depending to some extent upon the requirements imposed by theintended use of the wood. In lumber mill operations, for example, thebark does not interfere seriously with the sawing of lumber, and so ithas heretofore been left in place, to be eventually eliminated alongwith a considerable amount of waste wood in the cutting of rectangularcants and lumber from a round log. In preparing socalled peeler logs forcutting wood veneer in a lathe, it has been customary to first removethe bark in a rossing machine, but a considerable amount of wood isthereby wasted because the action of such machines does not stop at thecambium layer. In the barking of pulp logs, also, it is usuallydesirable to remove the bark cleanly from the wood in order to keep allbark out of the pulping process although no attention has heretoforebeen given to contamination of the discarded brake by the inclusion ofwood slivers and chips torn off by the rossing machines in conventionaluse.

With increasing utilization of bark products and increasing cost of woodit is becoming more important to keep the bark, as well as the wood,each free of contamination by the other. Conventional rossing machinesdo not accomplish this clean separation between the bark and the wood,with the result that if all the bark is removed some wood is .alsoremoved and the outer layer of wood is damaged to some extent in theremoval. Conversely, if the bark is to be kept free of wood, some barkis left on the log in bark removal processes heretofore employed. Otherobjections to conventional barking machines are their high initial costand high cost of operation, particularly because of their large powerdemands.

It is, therefore, an object of the present invention to provide animproved method of barking logs which will separate the bark cleanlyfrom the wood without slivering or otherwise damaging the wood andwithout including such wood chips and slivers along with the bark. Otherob- Jects of the present method are to effect bark removal more quicklyand with less expenditure of energy than in conventional barkingmachines, and to provide a method of barking logs which may be carriedout on a comercial scale with a relatively small investment in machineryand plant space, with relatively small power requirements and with a'minimum amount of handling of the logs. Another object is to provide abarking method which is suitable and practical for all logs to obtainpure bark, regardless of whether the wood is to be used for pulp, veneeror lumber.

In its broader aspects the method of the present invention comprises thecreation of a differential compression in the bark with respect to thewood, and movement of an area of compression relative to uncompressedareas, the compressive force being yielding to follow the contour of thelog and not sufliciently great to compress the wood. A moving pressurearea is imposed against the bark layer momentarily to compress and thenrelease the bark progressively in successive localized areas to causethe bark to break and separate itself from the underlying wood surfaceas the pressure area or wave moves over said areas. Such a pressure wavemay advantageously be created by pressing a rigid tool in asubstantially perpendicular direction against the surface of the barkand then moving said tool relatively over the surface of the bark tomove the compressing action to successive new localized areas whilecompressed areas are released to permit re-expansion of the bark behindthe moving tool. The tool may take various forms as will be pointed outhereinafter in connection with the detailed description of apparatus forcarrying out the method, but the best results appear to be accomplishedwith a tool having relatively small area in either line or spot contactwith the bark surface. When considerable force is applied to the tool ina direction-or line of action substantially perpendicular to the barksurface, the bark under the tool is momentarily compressed producing arather high degree of compression or strain in the cambium layer lyingagainst the sap wood. When. this compressive force is moved along thebark to create a moving localized pressure wave, it produces aseparation of the bark from the underlying wood causing the bark tobreak into pieces which cleanly separate from the wood without sliveringor otherwise damaging the surface layer of wood.

It is also believed that the traveling pressure wave operates to tensionthe bark as though by a rubbing action to raise a bulge ahead of thepressure zone, which pulls the bark off the wood surface. Liquidpressure from sap squeezed out of the cambium layer and sap wood aroundthe pressure area may also operate to separate this layer from the woodwhen there is considerable liquid present in this zone. Still othereffects not presently known or understood may also contribute inproducing the desired separating action, but it is not intended to limitthe invention by analytical explanations except as to the limitationsimposed by the appended claims.

In one form of machine which has been devised to carry out the steps ofthe method, the log to be barked is supported in a lathe for rotation ona horizontal axis. The pressure applying tool is carried on the end of apiston rod extending from an air cylinder disposed approximatelyradially with respect to the axis of rotation of the log. While the logis rotating air is admitted to the cylinder to press the tool againstthe bark surface with suflicient force to produce the above describedpressure wave in the bark layer without deforming the underlying wood.The cylinder is mounted in a fixed position on a lathe carriage or thelike so that as the log revolves the tool and the pressure wave itproduces-are caused to travel relatively around the log. This action ispreferably started at one or more stations alorg the log, the carriagebeing traversed along the log to move the tool or tools to new barkareas.

The method will be described in greater detail in connection with theaccompanying drawings illustrating a present form of barking machine forcarrying out the method, although it is to be understood that theapparatus may take other forms and that the present arrangement ofmachine elements is not necessarily essential to the successfuloperation of the method.

In the accompanying drawings:

Figure 1 is a cross sectional view through a machine arranged to carryout the method of the present invention on a log mounted therein;

Figure 2 is a side elevation view taken on the line 22 of Figure 1,showing the nature of the barking action accomplished by the presentmethod;

' Figure 3 is an enlarged detail view of the barking tool shown inFigure 1, the roller being illus trated in section;

Figure 4 is a fragmentary cross sectionai view showing a different formof barking tool which may be employed in the performance of the presentmethod, and;

Figure 5 is a similar view of a modification of the type of tool shownin Figure 4.

In the apparatus illustrated in the drawings the numeral I designates alog having an outer layer of bark ll adhering to the outer sap wood ofthe log at the cambium layer l2. Means are provided for rotating thislog with respect to a barking tool l3, but it is to be understood thatthe present method may be practiced by holding the log stationary andmoving the tool, and by producing other types of relative movementbetween the tool and the log than pure circular motion. The relativemotion may, for instance, be a combination of longitudinal and circularmotions. Any suitable means may be provided for supporting the log forrotation with respect to the tool II, the present barking machinecomprising essentially a large lathe having sufficient capacity toreceive logs of the desired length and diameter. The lathe illustratedhas a pair of face plates i4 and I integrally associated with large spurgears II and H by which they may be rotated by suite able drivingmechanism. The gear l6 and face plate I4 in the present instance aredriven by a small pinion 18' with the face plate and gear I! remainingstationary, although these elements may also be driven by another piniongear if desired. The log it has square cut ends to which are attachedthe plates l8 and I9 geometrically centered on each end surface. Theplate i8 is supported on a spindle and rotated by integral lugs or dogs2| projecting into the usual radial slots 22 in the face plate l4. Theplate I9 is supported by a spindle 23 which may be moved axially by ahand wheel 24 in chucking and un chucking the log. This chuckingarrangement provides for centering the log on the spindles so as toequalize. as far as possible, any eccentricity or lopsided growthwhereby the log is rotated substantially on its geometrical axis withoutregard to the position of the center of the growth rings of the wood.The power drive for the pinion i8 includes the usual clutch and speedchanging mechanism to control the surface speed of the log relative tothe tool l3. Other chucking arrangements may be devised for logs nothaving square cut ends.

The numeral 30 designates a rigid supporting member for a carriage 3|which may be traversed along the length of the log by means of a handwheel 32. The carriage 3| is provided with a cross slide 33 for=a toolsupport 34 which may be moved radially of the lathe axis by means of ahand wheel 35 to adjust a tool in accordance with the diameter of thework in the lathe. On the tool support 34 is fixedly mounted a base 36carrying an air cylinder 31 and a pair of slide bearings 38 for a pistonrod 40. The barking tool 63 is mounted on the end of the piston rod in aposition to engage and press in a substantially radial direction againstthe bark surface of the log as the latter rotates in the lathe, thecylinder 31 being of suflicient length to provide a piston rod stroke inexcess of variations in the radius of the log as chucked. Adjustment fordifferent size logs is made through crank 35 so that the piston will notreach either end of its stroke as the lobes and hollows on the barksurface pass under the barking tool.

Operating air for the cylinder 31 is introduced through a pipe 4! underthe control of a manual valve 42. The numeral 43 designates a pressuregauge and the numeral 44 an exhaust valve for relieving the pressure inthe cylinder when the valve 42 is shut off. This arrangement provides asingle acting pressure cylinder in which the piston rod may be retractedby hand when the valve 44 is opened, but a double acting cylinder may beused having a four way valve connected in the usual manner to retractthe piston rod by air pressure if desired. The gauge 48 indicates theoperating pressure in the cylinder, and the valve 42 is preferably of atype which may be cracked slowly and then closed to produce an operatingpressure less than the pressure in the line 4| when desired. I

Different forms of barking tool may be used in practicing the method ofthe invention. The tool I! comprises a roller 50 mounted on ballbearings 5| for rotation around a central pin 62 in a bifurcated block53 having a socket 54 receiving the end of the piston rod 40. In thepresent embodiment the roller 50 is relatively narrow and small indiameter in relation to the dimensions of the log, the optimumdimensions for the diameter and width of the roller being determinedprincipally in relation to the operating force exerted upon the pistonrod to produce the desired unit pressure against the bark. The roller inFigure 1 has a radius approximately equal to the thickness of the barkbut this relationship is not critical as the present roller produces asatisfactory barking action on bark several times as thick in relativedimensions.

The line 60 indicates the level of the spindle centers in the lathe,which is here shown as coinciding with the growth center of the log, andthe line 6! designates the axis of the piston rod G0. In Figure 1 itwill be noted that the piston rod axis BI is horizontal and slightlyabove the center of the lathe spindles. This relationship is notimportant to the use of the roller tool l3, but is of importanceinconnection with another form of barking tool to be presentlydescribed. The barking tool I; is thereby seen to have a line of actionon the line 6|, causing the relatively small cylindrical roller 50 to bepressed into the bark in a circular track around the log as the latterrevolves. The roller rides over the bark irregularities and produces atraveling pressure wave extending laterally forwardly and rearwardly onall sides of the roller, and inwardly through the cambium layer to therelatively hard sap wood surface underneath. The pressure of the airemployed in the cylinder 3| is sufficient to produce some compressivedeformation and crushing of the bark immediately under the rollerwhereby the roller has actual contact with the bark surface over aconsiderable portion of the projected area of the roller as shown.

In a barking operation the log is first chucked in the manner describedand the lathe put in operation to rotate the log in the directionindicated by the arrow 62. Compressed air is then admitted to cylinder31 to build up a desired indicated pressure in the gauge 43 to press thetool l3 against the bark surface with the necessary unit pressure on thebark. The barking operation may be started at any point along the log,but when a single barking tool is used it is most expedient to beginwith the first contact of the tool at one end of the log. Pressure ofthe tool causes pieces of bark extending several inches on either sideof the tool track to separate themselves from the underlying wood andbreak off from the surrounding bark leaving spots of bare wood exposed.As the log revolves and the tool moves horizontally, additional piecesof bark break off in the same manner until the log is substantially barkfree.

As the roller passes over the bark it alternately rolls and slides asbark fragments become wedged in the included angle between the solidbark surface and the arcuate surface of the roller. Since the includedangle between the roller and the bark surface widens from a zero valueat the point of tangency up to 90 degrees at the side of the roller, itis considered to be relatively unimportant whether the line of action 6|on the tool is directed on a level above the spindle level or coincidenttherewith. In any case, the included angle between the roller and thesolid bark surface forms a wedging space in which the unit pressureincreases from zero to a maximum at some point on the periphery of theroller. The point ofmaximum unit pressure appears to shift forwardly ofthe point of tangency when loose bark material piles up under the rollerto produce a sliding rather than a rolling contact, but in either casethe tool produces a compression pressure wave extending through thecambium layer of the bark and traveling around the log, which pressurewave is found to be effective in removing the bark from the log.

The optimum values of the maximum unit pressure and the speed of travelof the pressure wave depend upon the species of tree, the size of tree,thickness of bark, the condition of the bark, and other variables. Thecondition of the bark at the time of the barking operation is affectedby the conditions of growth under which the bark was formed, by theseason of the year in which the tree was cut, and by the nature andduration of the seasoning of the 10g between the time the ,by thenumeral ll.

tree was felled and the barking operation. The condition of the bark isalso, of course, affected by the latitude, altitude and climaticconditions of the locality where the tree grew. In view 01' thesemanyvariables which must be taken into consideration, applicants do notdeem it important to specify particular values for unit bearingpressures of the tool and relative speeds of the tool with respect tothe bark surface. It will. therefore, be apparent that the speed of thelathe and the operating pressure of the cylinder are to be regulated andcoordinated by experience in accordance with the type and surface areaof the barking tool to produce the mode of operation herein described.When different logs are received in the barking mill it becomesnecessary to change these variables just as adjustments must be made fordifferent kinds and conditions of wood in other wood and wood producttreating apparatus. It has been found "that when the air pressure is toolow or the lathe speed too great, bark is not satisfactorily removed,and, of course, it is obvious that there would be a certain minimum airpressure below which the tool would have no appreciable effect upon thebark. A high operating pressure, of course, increases the size of themachinery from a strength standpoint and increases the power demands ofthe lathe. Assuming the machine to be sufficiently strong and powerful,a limitation on the maximum operating pressure is imposed by the amountof damage to the wood surface which may be tolerated. In general, ahigher operating pressure removes bark more quickly. That is to say thatwith the optimum speed of rotation, fewer turns are required in the sametrack or region. However, if the operating pressure is too high acertain amount of slivering occurs in the sap wood layer, caused by thepressure of the tool against the log, which is objectionable bothbecause of damage to the wood and because of the inclusion of woodslivers in the removed bark. The general rule of thumb may, therefore,be advanced that it is advantageous to increase the operating pressureup to just less than the point where slivering of the wood occurs, toattain the maximum barking speed consistent with the desired quality ofthe product.

Figure 2 illustrates the action of the barking tool in removing bark inthe manner described. The numeral 55 designates successive tracks madeby the roller element 50 in different adjusted positions of the carriage3| along the log. For the purpose of illustrating the action of thebarking tool, it is assumed in Figure 2 that the carriage is maintainedin a fixed position until all the bark is removed from a particular zoneof the log, after which the carriage is moved to a new position torepeat the action on a new zone of bark. Thus the distance betweensuccessive tracks 55 indicates the amount of movement of the carriagebetween its successive positions. It is, of course, understood thatinstead of shifting the carriage in increments from one fixed operatingposition to the next, it may be moved slowly and continuously by a screwthread or other continuous feed or traversing mechanism.

In Figure 2 the bark has been completely removed from the left end ofthe log, exposin the bare sap wood in the region designated by thenumeral 56, the unbarked area being designated The log has accordinglymade several turns with the tool in its present position, making a track55 which is indicated by 7. definite lines on the drawing but which, infact, may not readily be visible to the eye until still more turns havebeen made. With the log turning in the direction indicated by the arrow62, it will be seen that some of the bark has already been removed fromthe previous passages of the tool thereover, and that in the passage ofthe tool depicted in the drawing most of the remaining bark has beenremoved, leaving in view at the instant depicted only the islands ofbark 51 and a peninsula of bark 58 behind the tool. Such islands andpeninsulas of bark may be sheared off in individual chunks when the toolnext encounters the edge thickness of bark, but if the bark does notyield immediately to a shearing action the roller will climb up on theouter surface of the bark and subject these areas to further pressuretreatment until the bark finally yields and becomes detached from theunderlyin wood. The piston rod 40 is moved back and- If the carriage 3!is traversed gradually the action is the same except that the track 55makes a continuous spiral so that the center of the roller never passesover the same point twice. Nevertheless, the pressure wave produced bythe roller passes repeatedly over each area of the log until it hasmoved into a new zone, the rate of traverse being regulated to produce amaximum rate of bark removal.

If higher air pressures are employed the length of the face of theroller 50 may be made cor respondingly longer for line contact insteadof spot contact to apply the pressure wave over a greater length of logto remove more bark in each 360 degrees of track. If the carriage istraversed by a continuous feed, the feed rate may be adjusted to ahigher speed when a longer roller is used.

This method of barking is very economical of mechanical energy. The airpressure supply for the cylinder 31 has very little demand thereonbecause its only function is to hold the barking tool resilientlyagainst the log. Also, relatively little energy is required to turn afairly smooth round log under the barking tool when the log is properlychucked in the lathe. Additional torque is required to produce ashearing action on the bark, and if the roller 50 is of such diameter inrelation to the bark thickness that considerable shearing action occursagainst the edges of islands and peninsulas of bark, then suflicienttorque must be supplied momentarily by motor or flywheel to meet theseadditional demands, but in return for this additional energy input ahigher speed of bark removal is obtained. On large diameter trunksections where the bark is unusually thick and rough on its surface, arelatively large adidtional amount of energy may be'required to performthe shearing function, but in such case there is an increased yield ofbark to justify the added energy requirements. On the whole, the presentmethod is much quicker and more economical in its power requirementsthan conventional methods of barking logs.

One explanation of the action of the pressure wave in initiallyloosening the bark from the wood is illustrated in Figure 1. The barklayer appears to be stretched and moved by the roller 50 to some extentin somewhat the manner that a dough sheet is stretched by a rolling pin,or a carpet is moved on the floor under a rolling wheel. The numeral 63designates a bulge raised by such stretching and movement, comparable tothe bulge raised in the dough sheet or carpet ahead of a rolling object,which bulge in the bark tends to raise the cambium layer underneath, asex= aggerately represented by the space 64 left between the bark and thewood. Applicants do not necessarily propose this explanation as thepredominant action of the roller, but merely mention the possibilitythat this effect contributes materially to the loosening of the bark,regardless of whether the barking tool takes the form of a roller orbutton.

However, even if the actual bark displacement, or movement, laterally byway of stretching is very small, or inconsequential, in a particularspecimen, it is neverthless evident that under the point or line ofapplication of pressure the relatively yieldable bark is locallycompressed against the relatively hard wood surface underneath. Thisdifferential compression tends to produce a concave curvature in thebark stratum to pull or lift the bark cambium layer off the undeformedwood surface around the perimeter of the pressure zone. Expressed interms of stress and strain the differential compression phenomenon maybe said to comprise a central zone of perpendicular compressionproducing bending strains in the bark extending outwardly beyond themargin of the compression zone, and perpendicular tension in the barkand between the bark and wood immediately around the compression zone.Thus the pressure wave is so-called because it produces in the barklayer a central zone of compression surrounded by a perimetric zone oftension which may be visualized asproducing a saucer-like deformation ofthe bark layer when the pressure is applied by point" contact. When thepressure is applied by line" contact the deformation is trough shaped.

When such a pressure wave is moved relative to the bark the tension zonemanifests itself as a bulge predominantly on its leading side, referredto the relative direction of motion, as shown in Figure 1. Thiseccentric strain pattern is believed to be due not only to lateralstretching or pulling of the bark asexplained above, but also to thefact that the bark does not quickly expand perpendicularly immediatelybehind the tool as a perfectly elastic medium. Mechanical hysterysis ofthe bark material would, of course, operate to make the radius ofcurvature of the bark depression less on the trailing side than on theleading side of the tool. Thus by moving the tool relative to the barkthe bending and tension strains are amplified on the leading side of thepressure center sufliciently to cause separation and breakage of thebark. As hereinabove mentioned, applicants do not preclude thepossibility that still other factors, presently unknown, may contributematerially to the loosening of the bark, but the foregoing explanationsappear to be consistent with the observed operation of the apparatus.

A different form of barking tool is shown in Figure 4. The tool 65 ismerely a steel button having a square face, with rounded edges, in aplane perpendicular to the piston rod 40. By reason of the position ofthe piston rod on the line 6| slightly above the level 60 of the lathespindles, there is a small included angle 66 between the face of thetool and the generally arcuate surface of the bark on the log. Thisproduces an eccentric loading of the tool with a region of maximum unitpressure along the trailing edge of the tool and a region of relativelysmall unit pressure on that part of the tool face which first encountersthe bark. This tool exerts a rubbing action which, by reason of theforce applied to the piston rod, creates a traveling pressure waveextending through the Cambium layer of the bark with the same generalresult produced by the previously described tool l3. On a relativelysmooth bark surface before any pieces of bark have been dislodged, theaction of the tool 65 is substantially the same as the action of thetool 13, but, after pieces of bark have broken out, the side of the toolexerts somewhat more shearing action against the edges of the barkislands and peninsulas than is exerted by the roller surface 52. Thisadvantage is desirable for rapid barking, but it imposes severe stresseson the mechanism when the bark is thick and tight. For this reason thebarking tools I 3 and 65 are interchangeable in the present apparatuswith the tool l3 operated on the line of action 61 which is found bestfor the tool 65. The two tools may thereby readily be interchanged toexert the most effective action on different types of bark. The tool 65,in general, imposes the same operating limitations as the tool 13.Higher operating pressures produce faster bark removal, but these mustnot be high enough to damage the sap wood and contaminate the bark withwood slivers when the tool rubs on the bare wood.

Another form of barking tool is shown in Figure 5. Here the tool 61 hasa rubbing face in a plane forming an angle 68 with a plane perpendicularto the pitson rod 40. The piston rod 40 may thereby be disposed with itsline of action coincident with the level line 60 through the lathecenters. The face angle 68 then becomes the included angle between thetool face and a tangent to the bark surface. As has previously beenstated, the roller tool l3 may also be employed on this line of action,thus making it interchangeable with the tool 61 as well as with the tool65.

Although only a singletool I3 has been shown in the drawings toillustrate the method of the invention it is apparent that a gang ofsuch tools may be mounted on individual piston rods in a plurality ofcylinders carried by the carriage 3| to increase the output of themachine and reduce r the carriage travel. Quick chucking means are alsodesirable to reduce the time and handling for each log.

Still further variations in the construction and arrangement ofapparatus for practicing the method will occur to persons skilled in theart, and all such modifications of the application of the method withinthe scope of the appended claims are included in the invention.

Having now described our invention and in what manner the same may beused, what we claim as new and desire to protect by Letters Patent is:

1. The method of barking a log such as used for the production of woodveneer, pulp and the like, comprising impressing against the surface ofthe bark an approximately radially directed compressive force over anarea of small dimensions relative to the diameter of the log to followthe contour of the log, and moving the compressive force longitudinallyand circumferentially of the log,

said force being of sufiicient intensity to compress the bark and causefailure of the bond between the bark and the log.

2. The method of removing the bark from logs such as used for theproduction of wood veneer,

pulp and the like, comprising applying against a small area of the barksurface on a log a continuous compressive force of suflicient intensityto cause the bark to break and separate from the log, and moving thepoint of application of said force relatively around and longitudinallyof the log and into hollows and depressions in the bark surface forremoving the bark from the log in the path of said movement.

3. The method of removing bark from logs as defined in claim 2 whereinthe compressive force is applied against the bark surface of the log insubstantially a radial direction.

4. The method of removing the bark from logs comprising supporting a logby its ends, applying a continuous compressive force against a smallarea of bark surface on the log of suflicient intensity to cause failureof the bond between the bark and the log, creating relative longitudinalmovement between the log and the point of application of said force, androtating the log to move the point of application of said force aroundsaid log and into hollows and depressions in the bark surface forremoving the bark from the log in the path of said movement.

5. The method of removing the bark from logs such as used for theproduction of wood veneer, pulp and the like, comprising applying alocalized pressure against a small area of the bark on a log, movingsaid pressure relatively around and longitudinally of the log and intohollows and depressions in the surface of the log, said pressure beingof sufficient intensity to cause the bark to break and separate from theunderlying wood surface.

6. The method of removing bark from legs as defined in claim 5 whereinthe surface of the log is moved under a rolling pressure.

7. The method of removing bark from logs such as used for the productionof wood veneer, pulp and the like, comprising imposing a localizedpressure against the bark within an area of small dimension relative tothe surface of the log and of sufficient intensity to cause the bark tobreak and separate from the log, and moving the area of application ofsaid pressure relatively around and longitudinally of the log to createa traveling pressure against the bark layer.

8. The method of removing bark from logs as defined in claim 7 whereinthe pressure imposed against the bark is a yieldable pressure.

9. The method of removing bark from logs as defined in claim 7 whereinthe pressure is suflicient to break the bark and cause it to separatefrom the log at the cambium layer but is insufilcient to crush the woodon the surface of the log.

ROBERT D. PAULEY. LOUIS A. MCCANNA.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 305,322 Merziger Sept. 16, 1884871,296 Russell et al. Nov. 19, 1907 1,277,808 Witham, Jr. Sept. 3, 19181,670,723 Hummel May 22, 1928 1,881,465 Ganes et a1 Oct. 11, 19321,951,084 Council Mar. 13, 1934 FOREIGN PATENTS Number Country Date125,776 Germany Dec. 4, 1901.

4,404 Australia Oct. 25, 1925

